Alternatives to Chess Tempo
The serious puzzle grinder's tool. If that's not for you - or you want to try something different - here are apps that overlap on features and use cases.

Chess King Learn
Chess King (CHESSQUEEN INC, ex-Convekta)
Huge Convekta course catalog in one app.
Free
4.8Web · iOS · Android

Chess.com
Chess.com, LLC
The default home of online chess.
Free · from $4.17/mo
4.5Web · iOS · Android

Lichess
Lichess (charity)
Free, open-source chess. Forever.
Free
4.8Web · iOS · Android

Chessable
Chessable (Chess.com)
MoveTrainer + spaced repetition for openings and tactics.
Free · from $11.99/mo
4.5Web · iOS · Android

ChessEndings
ChessEndings
Play endgames out against an opponent that never gives up.
Free · from €39 one-time
Web

Listudy
Arne Vogel
Free open-source spaced repetition for openings.
Free
Web

Aimchess
Aimchess (Chess.com group)
AI that finds your chess weaknesses and drills them.
Free · from $7.99/mo
4.1Web · iOS · Android

CT-ART 6.0
Convekta Ltd. (ChessOK)
The classic tactics trainer, now multi-platform.
From €24.99 one-time
Web · iOS · Android